Utterberg et al. U.S. Pat. No. 5,112,311 discloses a sliding body or sheath which is carried on a tubular set such as a fistula set for hemodialysis, having a winged needle at the end. There is a significant need to provide the maximum amount of protection to medical personnel against needle sticks, especially with respect to needles that are used in contact with blood. The sliding sheath of the cited patent can be brought forward to enclose the needle as the needle is retracted from the patient, so that the needle is immediately secured against accidental needle sticks by the sliding device. The wings of the needle, which are commonly used in conjunction with a variety of intravenous needles, slide within opposed slots of the needle protector of the cited patent, and are locked in place when the needle is fully withdrawn into the sliding sheath as described.
By this present invention, improvements are provided to the device disclosed in the above-cited patent. Specifically, the device of the prior art is typically placed on a needle set prior to use and the wings engaged in the slots. Even when the sliding sheath is retracted away from the needle as much as possible, medical personnel have found its presence to be inconvenient during the process of venipuncture and taping of the needle wings to the skin of the patient.
Also, by this invention, improvements in functioning are achieved by a modification of the shape of the slots of the sliding sheath or body through which the needle wings penetrate. Particularly, withdrawal of the needle from the patient can be facilitated in an axial movement, reducing the potential for the point to cause a hematoma. Also, advancement of the sheath about the needle is facilitated.
Thus, significantly improved needle protector sheaths are provided, some of which can be applied to a needle and attached tubing after the needle has been inserted into the vein of a patient. Additionally, other improvements over the prior art are found herein.
In accordance with this invention, a needle protector sheath is provided which comprises a body having a top wall, side walls, and at least partially open ends. A slot is formed in at least one of the walls, and preferably in each side wall, to slidingly receive a needle wing extending through each of the slots. The protector sheath may define an open, bottom aperture extending from end to end of the body to permit the sheath to be laterally applied to tubing connected to a winged needle. After such lateral application, the sheath or body can be advanced in sliding manner along the tubing to a position where the needle tip becomes recessed in the sheath, and the needle wing or wings extend through the slot or slots present. Thus some types of the sheath of this invention can be mounted on a needle set after the needle has been placed in a vein or a fistula.
Detents may be provided on the side walls adjacent the bottom aperture to help retain a winged needle, and its connected tubing, within the body of the protector sheath. The bottom aperture is proportioned to permit a needle, needle hub or its connected tubing to be inserted through the bottom aperture for laterally installing the protector sheath onto the tubing of the needle set.
The body of the protector sheath may further define a needle tip retaining wall which is typically formed between the top and side walls adjacent to one end of the body. Such a retaining wall may be positioned substantially parallel to the longitudinal axis of the body to define a closed pocket with the remainder of the body, for receiving a pointed needle tip which is carried within the protector sheath. This provides an added, desired sequestering of the needle tip for improved safety. Alternatively, the retaining wall may be positioned at an acute angle, for example about 30xc2x0 to 60xc2x0 to the longitudinal axis of the body, which also defines a closed pocket with the remainder of the body for needle tip retention. If desired, the retaining wall may be essentially perpendicular to the longitudinal axis of the body (or in fact, it may be a partial front wall) to form a barrier wall against which the needle tip may impinge, for further protection against accidental needle sticks.
It also is desirable for the slots of the protector sheath body to extend toward the sheath bottom as they extend toward an open slot end at one end of the body. This has been found to facilitate the easy withdrawal of a needle emplaced in the venous system of a patient, with the needle tip directed in the direction of the one end of the body. As the needle is withdrawn, the needle protector can receive the needle wings in the slots. Because of the extension of the slots toward the bottom of the body, the needle wings are more easily received and engaged by the slots as the needle is withdrawn, with the needle protector sheath being held stationary, so that the needle may be withdrawn rearwardly into the needle protector sheath. The slots preferably extend through one end of the body at the slot end nearest the bottom aperture.
As another aspect of the inventions disclosed herein, an elongated anchor member can extend forwardly from the body to be manually pressed to retain the protector sheath as the needle is being withdrawn from the skin of a patient, as broadly disclosed in the cited U.S. Pat. No. 5,112,311. By this invention, the anchor member may have a straight, major portion comprising most of the length of said anchor member. Also, the anchor member may define an outer end portion that bends away from the patient in position of use, typically as a curved shape rather like the tip of a ski. Thus, when the sheath of this invention is being advanced toward a position to receive the needle when the needle is to be withdrawn from the patient, the anchor member more easily slides over adjacent bandages and the like.
Preferably, the anchor also comprises a substantially flat, sheath-like extension of the top wall. Also, the anchor may join the top wall at a junction line which is defined by a line of bending weakness, to facilitate its downward bending when manually pressed.
The body of the protector sheath, which may be rectangular in cross-section, is preferably tapered by about 0.2 to 5 degrees to define a forward end of the body that is of less cross-sectional dimension than a rear end of the body. This small amount of tapering or xe2x80x9cdraftxe2x80x9d facilitates the molding of the sheath.
It is also a preferred embodiment for the slots to extend through a forward end of the body with the slots each defining upper and lower surfaces. A major portion of the slots preferably defines an acute angle to the longitudinal axis of the needle protector sheath so that most of the extent of the slots extends in such an acute angular relationship. Forward portions of the slots slope toward the top wall of the sheath as they extend toward the rear sheath end so that a needle is not bent or twisted as the sheath is advanced because of the acute angle of that forward slot portion. The rear portions of the slots may slope away from the top wall as they extend toward the rear end, to tip the point of the needle and hub having wings carried in the rear slot portions toward the top wall.
Forward end portions of the lower slot surfaces preferably extend at an acute angle to the longitudinal axis of the body to intersect the forward body end at a position that is substantially maximally spaced from the top wall. In those circumstances where a bottom wall is present, the lower slot surfaces preferably merge with the inner surface of a forward end portion of the bottom wall, to achieve such maximal spacing. The forward end portions of the upper slot surfaces may diverge from the lower slot surfaces and extend toward the top wall. Thus, wide slot portions are provided in each sidewall at the forward body end, which slot portions taper inwardly to communicate with the remainder of the slots, which remaining portions are substantially narrower. Thus, it becomes easy to advance the sliding sheath so that the front end thereof engages and captures the projecting wings of a needle hub, with the wings projecting outwardly through the slots.
Preferably, a major portion of each of the slots defines an acute angle to the longitudinal axis. Also, most of the length of the slots may be straight.
Thus, needle protector sheaths are provided which exhibit significant improvements in structure and functioning over those of the prior art.
The terms xe2x80x9ctopxe2x80x9d, xe2x80x9cbottomxe2x80x9d, and xe2x80x9csidexe2x80x9d as used herein are relative and exemplary in intent, and are not intended to exclude the use of a protector sheath of this invention in a different or varying position of spatial orientation.